The invention relates to a an oscillating motor comprising a magnetizable stator and a pivotally reciprocable armature and more particularly to such a motor provided with two coils which are arranged opposite each other and between which a magnetizable core extends, and a stator section provided with a magnet arranged parallel to the core. One of the magnet poles faces the core, and air gaps are formed between the stator and the core at those end faces of the coils which are remote from each other. Magnetizable pole elements of the armature are movable in the air gaps.
Such a motor is described in the article "Der schwingende Synchronlinearmotor mit Dauermagneten als Resonanz-Zugkrafterreger" in the magazine "Elektrotechnik und Maschinenbau", Jahrgang 96, Heft 10.
The known pivoting motor is constructed as a linear motor with two magnets and four mutually parallel air gaps. The pole elements of the armature are arranged in the air gaps and are movable along a straight path. In the operation condition the coils may be connected to an alternating-voltage source, the magnetic field thus produced in the coils cooperating with the permanent-magnetic field produced by the magnets. Under the influence of the magnetic forces which are then exerted on the sliding elements the armature can reciprocate linearly relative to the stator.
The armature of the known vibration motor is supported by elastic elements. Under operating conditions such a construction allows a movement of the armature in the transverse direction due to the retentive forces acting on the sliding elements. This has the drawback that the reciprocating motion of the armature is no longer perfectly linear and is not reproducible. Moreover, the clearance between the sliding elements and the stator and the core must be comparatively large in order to prevent the sliding elements from coming into contact with the stator and the core.
Therefore, the known pivoting motor is not suitable for uses in which the armature is required to follow exactly a predetermined path. For such uses complete control of the armature movement is necessary. The known motor must therefore be equipped with guide means for the armature. Guide means for linear motors are known per se, but such guide means, which generally comprise guide rods and linear bearing means, generally exhibit flexure under heavy loads. A linear oscillating motor provided with a known guide means provides satisfactory results only if the retentive forces are small. In the case of large retentive forces the requirements imposed on the armature movement cannot be very stringent. Moreover, in practice constructing a rectilinear guide mechanism for the armature with sufficient rigidity and suitable dimensions is found not to be a simple task due to the nature of the linear motor.